A variety of machines are used for producing portions in a portion control apparatus. In some portion control machines, sheet-form paper is used for separating the portions, the sheets often being dispensed from a paper feed system that feeds the bottom-most sheet of paper from a vertical stack of individual sheets.
One type of portion control machine forms patties of material, such as ground meat. Originally, the patties were formed by hand which involved unsanitary conditions resulting from human contact with the material, as well as a lack of uniformity in the weight, size and shape of the patties and limitations on the per worker output inherent with such labor intensive processes.
The portion control machines for forming patties overcame many of the shortcomings of hand-forming patties. These machines can produce patties in a sanitary manner that are substantially uniform in size, shape and weight and result in significant increases in per worker output.
Typically, a patty making machine has a mechanism that dispenses sheets of paper to be contacted with the patty to ensure separation of the patty from other patties or surfaces. The sheets prevent "sticking" of one patty or portion to another. The most prevalent type of sheet is of paper coated with wax. Some paper dispensing mechanisms use rolls of paper that are cut or torn to the desired length, but these rolls continuously must be replaced, which undesirably results in shut-down time for the patty making machine and, thereby, interrupting the patty making process.
Other paper dispensing mechanisms utilize precut sheets of paper that have one or more holes in the paper. The sheets are stacked with the aligned holes fitting over rods or pins from which the paper is torn during dispensing. Unfortunately, requiring rods to be threaded through the holes increases the difficulty in loading the paper. In addition, cutting or tearing the paper can undesirably result in small fragments of paper being deposited upon the patty. These and other disadvantages of precut sheets of paper having holes to facilitate stacking the sheets led to the use of a system wherein the sheets are provided with deformable elements, such as notches, in the side edges of the sheets.
More particularly, the referenced U.S. Pat. No. 5,137,172 shows a paper feed system suitable for use with a patty making machine to provide paper for separating the patties. A vertical stack of sheet-form paper is provided with a deformable element, such as a notch, on the side edge or edges thereof. A paper hopper is adapted to receive and temporarily retain the stack of paper sheets and is adapted to dispense the sheets by feeding the bottom-most sheet of paper from the stack. A male guide associated with the inside surface of the paper hopper engages the deformable element on the side edge of the sheets. A proximal end of the male guide adjacent to where the paper is dispensed temporarily retains the paper sheets in such a manner that the bottom-most sheet is dispensed without tearing the paper. In essence, the deformable elements, such as the notches, on the side edges of the sheets cause each individual sheet to be bent at an extreme angle when pulled past the male guide without tearing the paper.
Normally, the frictional force between the bottom-most sheet that is being dispensed and the next sheet in the stack is insufficient to pull the next sheet free from the guide, as it is not sufficient to overcome the "hold back" force resulting from the extreme bend required to free the paper from the guide. Accordingly, the next sheet is maintained within the paper hopper by its deformable element, and thus the paper should be dispensed only a single sheet at a time.
However, problems still have been encountered with certain sheet-form paper stock wherein there still is a tendency to pull two sheets of paper at a time if the paper feed system is not adjusted properly. Adding a more severe bend to the deformed or notched paper to increase its "hold back" force might be considered a solution to this problem, but it has been found that there is a tendency to tear the paper if it must be deformed too severely.
Another problem that continues to be present in paper feed systems for such sheet-form paper is that thinner sheets have a tendency to bow downwardly and fall out of the support means of the system. The feed mechanisms used to deposit the separating sheets between the patties or portions require that the sheet be supported under two of its opposite edges. More particularly, the sheets are fed along a support means which normally includes a pair of side rails which support the two opposite side edge areas of the sheets. While supported, a patty or portion is deposited on the top of a sheet which is then accelerated downward to the top of a stack below. Repeated positioning of additional sheets and subsequent depositing of the portions forms a stack of interleafed patties. Thinner sheets, such as on the order of 0.002 inches thick, have a tendency to fall down between the side support rails due to their own weight, even before a portion is deposited on the sheet. It would be advantageous to have a "stiffer" interleaf sheet so that it remains in position and does not fall out of the support rails during the stacking process.
The present invention is directed to a unique solution to the above-identified problems by providing a means for stiffening the sheets so that they do not fall through the support means, and particularly providing a sheet without adding significant cost. In addition, the stiffening means of the invention can be used to reinforce the deformable elements or notches at the side edges of the sheets to increase the "hold back" forces necessary to allow a bottom-most sheet to be pulled away from the next sheet in a stack thereof.